1. Technical Field
The present invention relates to a system and method for managing waste heat discharged from an electric vehicle, which can effectively use the waste heat generated from an onboard charger (OBC) or a motor of an electric vehicle to heat the electric vehicle, and can improve the fuel efficiency of an electric vehicle by heating a motor using the waste heat generated from the onboard charger (OBC).
2. Description of the Related Art
The term “electric vehicle” refers to a vehicle that uses electricity as its main source of power, that is, a vehicle that is equipped with a system for charging a battery with electricity and then supplying the electricity to a motor as a drive source. For example, there are electrically-rechargeable vehicles, hybrid vehicles, fuel-cell vehicles, and the like.
An electric vehicle is provided with an onboard charger (OBC, slower charger) to charge the battery. The onboard charger (OBC) is equipment for charging a battery by connecting the battery to a household 110V or 220V power source. Further, such an electric vehicle is provided with an LDC (low voltage DC to DC converter, voltage converter) so that battery power can be used to operate electronic components within the vehicle. Furthermore, such an electric vehicle is provided with an inverter and a motor to transfer drive force accordingly.
The OBC, LDC, inverter and motor of the electric vehicle are all components that generate waste heat. In the electric vehicle, waste heat is generated from the OBC while a battery is charging, is generated from the inverter and motor while the electric vehicle is running, and is generated from the LDC while the electronic components are operating.
If such inventive means are suitably utilized, the limitations associated with battery life can be reduced because the entire fuel efficiency of an electric vehicle can be increased through efficient reuse of this heat, and, particularly, the fuel efficiency of the electric vehicle in winter can be increased by preheating the inverter or the motor.
However, as shown in FIG. 1, the conventional heat exchange system for an electric vehicle is configured so that waste heat cannot be used, because a positive temperature coefficient (PTC) heater 10 and blower 12 consume additional electricity to heat the interior of the electric vehicle, and because the motor compartment is provided with a fluid pump 20, an LDC 30, an inverter 40, a motor 50 and an OBC 60 connected in series with each other and is cooled by operation of a fan 72 while air is passed through a radiator 70.
Furthermore, although the waste heat generated from the OBC 60 is used in this system, the waste heat leaks from the radiator and is separated from and not used to heat the interior of the electric vehicle, and thus the waste heat is not efficiently used.
The OBC 60 functions to charge a high-voltage battery by boosting the voltage of a household alternating power source using a transformer and then converting the household alternating power source into DC power source using a rectifier when the high-voltage battery must be recharged, in addition to the rapid charge of the high-voltage battery while the vehicle is plugged into a charging station. In order to prevent the OBC 60 from overheating while charging the high-voltage battery, the water pump 20, the radiator 70 and the fan 72 are operated so that the temperature of the OBC 60 does not reach a threshold temperature. However, due to the architecture and configuration of this system, unnecessary heat transfer occurs because the OBC 60 is disposed within the circulating cycle in order to cool the motor 50, the inverter 40 and the like even while the electric vehicle is running.
Therefore, a system and method of compensating for the insufficient battery performance of the electric vehicle by efficiently using the waste heat generated from the OBC 60 and the motor 50 are required.